An appendix forms part of this application. The appendix, which includes a source code listing relating to an embodiment of the invention, includes 691 frames on 8 microfiche.
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This invention relates to synchronizing incompatible databases.
Databases are collections of data entries which are organized, stored, and manipulated in a manner specified by applications known as database managers (hereinafter also referred to as xe2x80x9cApplicationsxe2x80x9d). The manner in which database entries are organized in a database is known as the data structure. There are generally two types of database managers. First are general purpose database managers in which the user determines (usually at the outset, but subject to future revisions) what the data structure is. These Applications often have their own programming language and provide great flexibility to the user. Second are special purpose database managers that are specifically designed to create and manage a database having a preset data structure. Examples of these special purpose database managers are various scheduling, diary, and contact manager Applications for desktop and handheld computers. Database managers organize the information in a database into records, with each record made up of fields. Fields and records of a database may have many different characteristics depending on the database manager""s purpose and utility.
Databases can be said to be incompatible with one another when the data structure of one is not the same as the data structure of another, even though some of the content of the records is substantially the same. For example, one database may store names and addresses in the following fields: FIRST_NAME, LAST_NAME, and ADDRESS. Another database may, however, store the same information with the following structure: NAME, STREET_NO., STREET_NAME, CITY_STATE, and ZIP. Although the content of the records is intended to contain the same kind of information, the organization of that information is completely different.
It is often the case that users of incompatible databases want to be able to synchronize the databases. For example, in the context of scheduling and contact manager Applications, a person might use one Application on the desktop computer at work while another on his handheld computer or his laptop computer at home. It is desirable for many of these users to be able to synchronize the entries on one with entries on another. However, the incompatibility of the two databases creates many problems that need to be solved for successful synchronization. The U.S. patents of the assignee hereof, Puma Technology, Inc., of San Jose, Calif. (U.S. Pat. Nos. 5,392,390 and 5,684,990, incorporated by reference herein) show two methods for synchronizing incompatible databases and solving some of the problems arising from incompatibility of databases. However, other problems remain.
Some database Application run on computer systems with very limited storage capacity, such as handheld computers. It is often desirable to synchronize the databases on these devices with databases on larger computers such as desktop computers which have much higher storage capacity. However, a straight synchronization between the Applications on the two devices may result in storage capacity of the smaller devices being mostly consumed with the records from the larger device, rendering the smaller device inoperable.
In a first aspect, the invention allows comparison of records from two different databases where at least one of the databases is subject to rules of data value to which the other database is not subject. The rules of data value of one database are used to change copies of the records of the other database so that a meaningful comparison can be made.
The invention features a computer implemented method of synchronizing records of first and second databases, wherein at least one field of records of the first database is subject to a first rule of data value to which the corresponding field of records of the second database is not subject. The first rule of data value of a field of the first database is used to modify copies of the content of corresponding fields of records of the second database. Thereafter, the content of the modified copies is compared to the content of the corresponding field of the first database, and synchronization actions are taken based on the outcome of the comparison.
In preferred embodiments, at least one field of records of the second database is subject to a second rule of data value to which the corresponding field of records of the second database is not subject, and the second rule of data value is used to modify copies of the content of corresponding fields of records of the first database; and the content of modified copies of the content of the first database is compared to modified copies of the content of the second database.
The invention may take into account rules of data value at the time of comparison. For example, two text fields may be compared only up to the character limit of one of them.
The invention provides a method of synchronizing multiple databases of different Applications. A database""s record, when written in another database may be tagged with a unique mark identifying the source of the record. These tags may be used to filter out only those records which should be synchronized. The tags may be attached when the records are unloaded to the databases.
The invention also provides for using certain design characteristics of certain Applications to speed up the synchronization process. Some Applications provide information for keeping track of which records were changed, deleted, or added since the last synchronization. The invention uses these features to speed up the synchronization process by focusing only on those records which have been affected since the last synchronization.
The invention may be implemented in hardware or software, or a combination of both. Preferably, the technique is implemented in computer programs executing on programmable computers that each include a processor, a storage medium readable by the processor (including volatile and non-volatile memory and/or storage elements), at least one input device, and at least one output device. Program code is applied to data entered using the input device to perform the functions described above and to generate output information. The output information is applied to one or more output devices.
Each program is preferably implemented in a high level procedural or object oriented programming language to communicate with a computer system. However, the programs can be implemented in assembly or machine language, if desired. In any case, the language may be a compiled or interpreted language.
Each such computer program is preferably stored on a storage medium or device (e.g., ROM or magnetic diskette) that is readable by a general or special purpose programmable computer for configuring and operating the computer when the storage medium or device is read by the computer to perform the procedures described in this document. The system may also be considered to be implemented as a computer-readable storage medium, configured with a computer program, where the storage medium so configured causes a computer to operate in a specific and predefined manner.
Other features and advantages of the invention will become apparent from the following description of preferred embodiments, including the drawings, and from the claims.